Biodiversity of ecosystems in an arid setting: The late Albian plant communities and associated biota from eastern Iberia

resulting canopy acting as a barrier to pollen transport in a fashion analogous to modern stands of Araucaria columnaris in New Caledonia and A. angustifolia in Brazil [159] and a pre- dicted poor species richness for the stand [170]; (ii) mixed conifer communities with Cupres- saceae, Podocarpaceae or/and Cheirolepidiaceae conifers constituting single-tiered or two- tiered woodlands, the latter with emergent araucarians. It would be reasonable to assume the existence of a transition from woodlands to more open, savanna-like, vegetation structures constrained by local edaphic conditions and the presumed arid to semi-arid conditions at a regional scale. The presence of Araucariaceae in hinterland vegetation could also be regarded as plausible, but it is likely not to have produced the recovered palynological signal given the low transport capacity of the araucarian pollen. Conversely, the ubiquity of Cheirolepidiaceae in pollen assemblages suggests a more efficient dispersal and that their contribution to the mixed conifer association described above might not have been that significant. • Salt marshes and swamps Mega and mesofloral assemblages from the Maestrazgo Basin are characterised by abun- dant Frenelopsis. While the genus has been associated with brackish coastal marshes when found in the mid-Cretaceous of Europe [106, 171, 172], it seems likely that the constituting species exhibited more diverse palaeoenvironmental affinities. In the three outcrops, the genus is represented by F. turolensis (Fig 11B), and/or F. justae (Fig 11E). While F. turolensis has

Fig 17. Conceptual palaeoartistic reconstruction of the late Albian wet interdunes in the fore-erg from the Maestrazgo Basin (eastern Spain). This environment developed near the Tethys, where (A) coastal forests with Araucariaceae grew. The riparian places of the wet interdunes (oasis) (B) were covered by fern and angiosperm vegetation. (C) Fresh water/brackish aquatic angiosperms inhabited wet interdunes. (D–E) Xerophytic plant community involving Cheirolepidiaceae, Cupressaceae (D) and other gymnosperms groups such as Bennettitales, Cycadales (Monosulcites/Cycadopites-producers) and Gnetales (Equisetosporites-producers) (E) that integrated arid woodlands. https://doi.org/10.1371/journal.pone.0282178.g017 PLOS ONE Late Albian desert biota from Iberia PLOS ONE | https://doi.org/10.1371/journal.pone.0282178 March 2, 2023 36 / 51